Download AN10389 Getting started uClinux with LPC22xx

AN10389
Getting started uClinux with LPC22xx
Rev. 01 — 15 February 2007
Application note
Document information
Info
Content
Keywords
uClinux, ARM LPC22xx
Abstract
This application note describes how to use uClinux on NXP’s LPC22xx
series ARM MCU: setup Linux environment, system configuration, build
and load image files as well as simple introduction on uClinux
development.
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
Revision history
Rev
Date
Description
01
20070215
Initial version
Contact information
For additional information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
2 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
1. Introduction
1.1 About uClinux
uClinux – Micro-C-Linux -- is a Linux derivative intended for microcontrollers without
Memory Management Unit (MMU). It’s free and open source software under GNU Public
License.
uClinux as an operation system includes Linux kernel releases for 2.0, 2.4 and 2.6 as
well as a collection of user applications, libraries and tool chains. The uClinux is much,
much smaller than Linux kernel while retaining the main advantages of Linux OS:
stability, superior network capability and excellent file system support.
For more about uClinux, refer to its official website via
http://www.nxp.com/external/uclinux.
1.2 About LPC22xx
The 16-bit/32-bit LPC2000 family is based on a 1.8 V ARM7TDMI-S core operating at up
to 60 MHz together with a wide range of peripherals including multiple serial interfaces,
10-bit ADC and external bus options.
LPC22xx series have configurable external memory interface with up to four banks, each
up to 16 MB and 8/16/32-bit data width. With their 144-pin package, low power
consumption, various 32-bit timers, 8-channel 10-bit ADC, PWM channels and up to 9
external interrupt pins, these microcontrollers are particularly suitable for industrial
control, medical systems, access control and point-of-sale. Number of available GPIOs
ranges from 76 (with external memory) through 112 pins (single-chip).
For more about the LPC22xx, refer to the microcontrollers section of the NXP website
http://www.nxp.com/products/microcontrollers.
1.3 uClinux for LPC22xx
Since its release in 1998, uClinux has supported wide range of CPU architectures as
M68K, ARM, PowerPC, V850, etc.
LPC22xx is based on supported ARM7 processor. While with up to 64 MB external
memory available, LPC22xx can fit for the relative big memory requirement of uClinux
(2 MB at least).
Note that LPC21xx series can’t run uClinux since its limited internal memory size.
2. Setup environment
2.1 Install Linux on the PC
To begin uClinux based development, a PC Linux environment is necessary.
To setup Linux environment, there are 3 ways:
1. Setup Linux on PC
Buying distribution CD-R or downloading Linux images from website, e.g., Red Hat Linux
9.0 on http://www.nxp.com/external/redhat, and then install Linux on your PC according
to its installation guide step by step. By configuring, you can get a dual-boot system:
Windows and Linux.
Please be sure there is enough memory space on your PC beforehand.
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
3 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
This way is suitable for single users.
2. Telnet to Linux server through intranet
To setup a Linux server is a good way for group users.
The telnet utility “Cuteftp, secureCRT, etc.” can be obtained from internet free.
3. Using Cygwin
Cygwin is a Linux-like environment for Windows, which can be downloaded from
Cygwin’s website located at http://www.nxp.com/external/cygwin.
It can be used in small application development or quick verification. Usually Cygwin is
not recommended for formal uClinux/Linux development.
2.2 Grab source code packages
To begin your first step on uClinux development, below is the list that you have to grab
on your Linux PC.
1) uClinux distribution
The easiest way to get started with uClinux is to download a copy of uClinux-dist from the
uClinux.org site via http://www.nxp.com/external/uclinuxdist.
2) uClinux-2.6 Kernel
You could find the latest uClinux/ARM kernel patch at:
http://www.nxp.com/external/opensrcsamsung
At the download section, you'll find the link of the original kernel package and the latest
linux-2.6.x patch under the kernel directory of the Public Linux Archive:
http://www.nxp.com/external/kernel/pub
3) NXP LPC22xx patch
From NXP’s support engineers or download from maillist of
http://www.nxp.com/external/uclinux, you could get the uClinux patch and kernel patch
against linux-2.6.x plus the above patch for LPC22xx.
http://www.nxp.com/external/mailman/2005-June
Name: uClinux-Philips-LPC22xx.tar.gz
For updating info, please pay attention to the maillist of uClinux official website.
2.3 Make source code tree
After gathering all files for first compilation (on this guide, the downloaded files are
gathered on ~/incoming), we should make up them together.
1) Untar the uClinux distribution
On a directory which has enough free available space (> 2 GB?), untar the uClinux
distribution:
[root@mylinux /]# tar -zxvf ~/incoming/uClinux-dist-20040408.tar.gz
Let's look around what we have on the uClinux-dist directory:
[root@mylinux /]# cd uClinux-dist/
[root@mylinux uClinux-dist]# ls -al
total 104
drwxr-xr-x 15 1000 users 4096 Apr 8 09:27 .
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
4 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
drwxr-xr-x 28 root root 4096 Apr 27 20:32 ..
-rw-r--r-- 1 1000 users 18007 Apr 8 09:13 COPYING
drwxr-xr-x 3 1000 users 4096 Apr 8 09:13 Documentation
-rw-r--r-- 1 1000 users 9305 Apr 8 09:13 Makefile
-rw-r--r-- 1 1000 users 4934 Apr 8 09:13 README
-rw-r--r-- 1 1000 users 1743 Apr 8 09:13 SOURCE
drwxr-xr-x 2 1000 users 4096 Apr 15 15:19 bin
drwxr-xr-x 3 1000 users 4096 Apr 8 09:27 config <-- the configuration files for
userland and etc.
drwxr-xr-x 11 1000 users 4096 Apr 8 09:27 freeswan <-- IPsec implementation
drwxr-xr-x 68 1000 users 4096 Apr 8 09:23 glibc <-- Yes, the GNU C library.
drwxr-xr-x 18 1000 users 4096 Apr 8 09:28 lib <-- many libraries ported to uClinux
include uC-libc.
drwxr-xr-x 15 1000 users 4096 Apr 8 09:27 linux-2.0.x <-- uClinux 2.0.x kernel
drwxr-xr-x 16 1000 users 4096 Apr 8 09:27 linux-2.4.x <-- uClinux 2.4.x kernel
drwxr-xr-x 18 1000 users 4096 Apr 8 09:27 linux-2.6.x <-- uClinux 2.6.x kernel
drwxr-xr-x 3 1000 users 4096 Apr 8 09:26 tools <-- utilities for romfs install and
etc.
drwxr-xr-x 17 1000 users 4096 Apr 8 09:27 uClibc <-- the uClibc, from uclibc.org.
Differ to uC-libc.
drwxr-xr-x 174 1000 users 4096 Apr 8 09:27 user <-- the “userland”. The
applications that is ported.
drwxr-xr-x 44 1000 users 4096 Apr 8 09:27 vendors <-- the configuration files for
each vendor/models.
2) Make a new linux-2.6.x kernel from the scratch
The kernel version of linux-2.6.x directory in the 20040408 distribution is “linux-2.6.2uc0”. We need another kernel with newer kernel version for uClinux/ARM 2.6, here.
[root@mylinux uClinux-dist]# tar -jxvf ~/incoming/linux-2.6.11.8.tar.bz2
Now we have got the whole linux-2.6.11.8 codes, and need to patch the kernel with the
Samsung patch.
[root@mylinux uClinux-dist]# gzip -dc ~/incoming/linux-2.6.11.8-hsc0.patch.gz |
patch -p0
3) Add NXP LPC22xx patch
You should have had two compressed files for LPC22xx.
3.1) LPC22xx patch against Linux kernel
The patch is against linux-2.6.11.8 kernel plus the Samsung patch.
1
[root@mylinux uClinux-dist]# gzip -dc ~/incoming/linux-2.6.11.8lpc22xx.patch.gz | patch -p0
You should see the codes that are patched in some directories that contains “lpc22xx”
string. You can use the directory name “linux-2.6.11.8” for your uClinux 2.6 kernel
directory without further operation. However, I recommend to use the kernel directory
name to “linux-2.6.x” because it is more convenient.
So you don't need the linux-2.6.x directory which is included in the uClinux-dist.
2
[root@mylinux uClinux-dist]# rm -rf linux-2.6.x/
And we rename the newer patched kernel directory to “linux-2.6.x”.
3
[root@mylinux uClinux-dist]# mv linux-2.6.11.8 linux-2.6.x
3.2) LPC22xx patch against uClinux distribution
Patch the file uClinux-dist-lpc22xx.patch.gz:
[root@mylinux uClinux-dist]# cd..
4
[root@mylinux uClinux]# gzip -dc ~/incoming/uClinux-dist-lpc22xx.patch.gz |
patch -p0
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
5 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
The patch is for the new vendor/product item. The result:
5
[root@mylinux uClinux-dist]# cd uClinux-dist/vendors
6
[root@mylinux vendors]# cd Philips/LPC22xx
7
[root@mylinux LPC22xx]# ls
8
config.arch
config.uClibc
inittab
motb
rc
9
config.linux-2.6.x
config.vendor
Makefile
passwd
3.3) Others
Since linux-2.6.10 and later version, the armnommu and arm architecture are combined,
user need modify file below:
uClinux-dist/vendosr/config/armnommu/config.arch line 41
from ARCH = armnommu
to ARCH= arm
An overview of the uClinux source code tree is shown in Fig 1.
uClinux-dist
config
configuration files for buid
Documentation
miscellaneous documents
Linux-2.0.x
the older uC-libc
uClinux-2.0
Linux-2.4.x
uClinux-2.4
Linux-2.6.x
uClinux-2.6:
-init, kernel, arch, fs, drivers, etc.
tools
uClibc
tools for romfs, etc.
the newer uClibc
user
application programs
vendors
Vendor/products:
Atmel, NXP, Samsung, etc.
Fig 1. uClinux source code tree
2.4 Get and install cross toolchain
1) Get ARM-ELF toolchain
Since the linux 2.6 kernel code uses some new features of newer binutils, you need a
newer ARM-ELF toolchain for kernel compilation than the one on the
http://www.nxp.com/external/uclinux website. You could find the latest toolchain at the
same place as the kernel and patch download section above, under the Toolchains
section.
http://www.nxp.com/external/opensrcsamsung/download
2) Install the toolchain
At the root directory execute the arm-elf-tools-20040427.sh like:
10
[root@mylinux /]# /bin/sh ~/incoming/arm-elf-tools-20040427.sh
2.5 Hardware platform
The hardware tools needed:
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
6 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
• LPC22xx development board and power supply for the board
• In-Circuit emulator, e.g. Multi-ICE by ARM company
• A PC with serial port and parallel or USB port for Emulator
• A serial cable
Besides the above necessary equipment, network cable and/or USB cable and others
may be needed according to system requirement.
A uClinux development system is shown in Fig 2.
JTAG
interface
LPC22xx board
In-Circuit
Emulator
GNU tools@Linux
and
ADS@WinXP
Power Supply
Serial Connection
Fig 2. Hardware platform for uClinux development
3. System configuration
System configuration is to configurate the uClinux system options, customize
functionality and make the image file size variable meanwhile.
We need setup the configuration for kernel, file systems and user applications.
11
[root@mylinux uClinux-dist]# make menuconfig
3.1 Distribution configuration
At the first Main Menu, Select the “Vendor/Product Selection” as shown in Fig 3.
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
7 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
Fig 3. Main menu
Select “Philips” for the “Vendor”, and “LPC22xx” for the “Philips Products” (see Fig 4).
Fig 4. Vendor/product selection menu
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
8 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
You can go back to main menu with 'esc' key or “Exit” button.
At the Main Menu, Select the “Kernel/Library/Defaults Selection”. And Select “linux-2.6.x”
for the “Kernel Version”, and “uClibc” for the “Libc version”.
And toggle the whole menus shown in Fig 5.
Fig 5. Kernel/library/defaults selection menu
With the first “default all settings”, the configuration files in the vendors directory is
loaded.
With the second “Customize kernel settings”, we can edit the kernel configuration.
The third “Customize Vendor/User settings” is for configuration of applications and
libraries configuration for making the romfs.img which will be the root file system of the
kernel.
With the final “Update Default Vendor settings”, your changes on the kernel and user
application configuration will be saved on the vendors/product directory.
In your developing or debugging stage, you can toggle the Kernel Settings and/or User
Settings only.
You can go back to main menu with 'esc' key or “Exit” button, and do again for saving
dialog. And save it!
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
9 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
3.2 Kernel configuration
If you follow the steps in “confirm the configuration files” above, your kernel should get
configured.
Let's have a look at some related configuration items as shown in Fig 6.
Fig 6. Linux kernel configuration menu
In the System Type option, the SRAM/FLASH base, address and size, the Oscillator
Frequency (Fosc) should be consistent with your board. The ARM Core Clock (Fcclk) is
your target CPU frequency.
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
10 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
Fig 7. System type menu
Fig 8. LPC22xx options menu
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
11 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
In the following General Setup option, please note the ‘kernel command string’ (Fig 9).
The initial ramdisk base, address and size can be changed according to your romfs.img
size.
Fig 9. General setup menu
For the serial and console support, please enter into the option Character deviceÆSerial
drivers (see Fig 10). The UART of NXP LPC22xx is 16c550 compatible, so toggle two
following items for serial and console input/output.
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
12 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
Fig 10. Serial drivers menu
For file systems options, the romfs(read-only) acts as the root file system which is
necessary (see Fig 11), whereas the ext2 is read-writable but it consumes significant
memory space. You can determine to select ext2 or not or even other file systems
according to your memory size and your application.
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
13 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
Fig 11. File systems menu
3.3 Application/library configuration
On this menu, you don't need fix anything for now. Look around the configurations and
simply “exit” and save.
Only a kindly prompt that you can see an item:
Miscellaneous Applications--->
[*] hello
When you try to develop an application program “hello”, it will appear here. To toggle it
will make it to be executable command of your uClinux system.
4. Build image
4.1 Make
We are ready to make the whole bunch. Simply type:
[root@mylinux uClinux-dist]# make
For linux-2.4.x, you should do “make dep” before “make”. But linux-2.6.x don't need to. It
will compile the whole kernel and uClibc, user applications, and make the image files.
4.2 The results
You should get the files in the image directory like:
[root@mylinux uClinux-dist]# ls -al images
total 3036
drwxr-xr-x 2 root root 4096 Apr 27 22:13 .
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
14 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
drwxr-xr-x
-rw-r--r--rwxr-xr-x
-rwxr-xr-x
-rw-r--r--
17 1000 users 4096 Apr 27 22:13 ..
1 root root 1540272 Apr 27 22:13 image.bin
1 root root 45912 Apr 27 22:13 linux.data
1 root root 704856 Apr 27 22:13 linux.text
1 root root 789504 Apr 27 22:13 romfs.img
[root@mylinux uClinux-dist]# ls -al linux-2.6.x/linux*
-rwxr-xr-x 2 root root 499433 Apr 27 22:11 linux-2.6.x/linux
-rwxr-xr-x 2 root root 15499433 Apr 27 22:11 linux-2.6.x/linux.bin
If you get the same files, you've the whole kernel and rootfs image.
The linux.bin is the kernel image while the large file "linux" includes the debugging
symbols. The "romfs.img" is the file system image.
"linux.bin" and "romfs.img" are the target images that will be programmed and run in the
target board.
5. Load image
5.1 Before loading
Before loading Linux kernel and file system images, let’s do some base jobs and know
some general knowledge.
5.1.1 Interrupt vector table
For LPC22xx, the interrupt vectors can be mapped to different memory space. The 4
mapping modes are controlled by the MEMMAP register of LPC22xx: boot block, internal
Flash, intenal RAM, or external memory. For details about mapping
The Linux system will generate its own interrupt vector table at the beginning address of
SRAM automatically. E.g. 0x8100 0000.
So we need to set up a direct link from LPC22xx interrupt vectors to Linux system
interrupt vectors.
User should program some code at internal or external flash and make it direct to Linux
interrupt vector table.
E.g.
CODE32
AREA
ENTRY
Reset
LDR
LDR
LDR
LDR
LDR
DCD
LDR
LDR
ResetAddr
UndefinedAddr
SWI_Addr
PrefetchAddr
DataAbortAddr
Nouse
IRQ_Addr
FIQ_Addr
vectors,CODE,READONLY
PC, ResetAddr
PC, UndefinedAddr
PC, SWI_Addr
PC, PrefetchAddr
PC, DataAbortAddr
0xb9205f80
PC, IRQ_Addr
PC, FIQ_Addr
DCD
DCD
DCD
DCD
DCD
DCD
DCD
DCD
ResetInit
0x81000004
0x81000008
0x8100000c
0x81000010
0
0x81000018
0x8100001c
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
15 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
5.1.2 Bootloader
Bootloader is an independent part from OS kernel, which will do necessary jobs before
kernel booting:
-
Necessary system initialization
-
Load uClinux images to specific position
-
Jump to kernel start and run
Bootloader is the very first program launched before uClinux kernel startup.
Besides the above basic functions, a bootloader can be designed with more capabilities
as:
-
Transfer kernel parameters from bootloader to kernel
-
Download image files from PC to board
-
Program board flash
-
Initialize some peripheral devices for better debugging: UART, Ethernet interface,
etc.
-
Etc.
A user can design his or her own bootloader to implement basic function or to port some
powerful bootloaders. e.g. U-Boot, blob, vivi, lilo, etc.
Here is a popular U-boot website for reference, which is a combination of PPCBoot and
ARMBoot and is quite suitable for PowerPC and ARM CPU families.
http://www.nxp.com/external/sourceforge/projects/u-boot
We can also download a uClinux bootloader for LPC22xx by a German developer:
http://www.nxp.com/external/ulrichradig
5.2 Load to RAM
Usually in the debugging stage, the kernel and fs will be loaded to external SRAM.
-
Some registers should be initialized before loading, e.g., PINSEL, BCFG, MEMMAP,
etc.
-
Load uClinux kernel and fs image to specified address
-
Jump to kernel start address and run
Here using the ADS environment as example.
Open System Views ÆCommand Line Interface in the AXD debugger and type “ob
d:\ess\config.ini” in the window. Below is the content of config.ini file.
setmem 0xE002C000 0x80000005 32
setmem 0xE002C014 0x0f814924 32
setmem 0xFFE00000 0x2000aeef 32
setmem 0xFFE00004 0x20007c67 32
setmem 0xFFE00008 0x1000ffef 32
setmem 0xFFE0000c 0x0000ffef 32
setmem 0xE01FC040 0x01 8
lb d:\ess\linux.bin 0x81008000
lb d:\ess\romfs.img 0x81200000
pc 0x81008000
r
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
16 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
5.3 Load to flash
After the debugging stage, we need manage to program the bootloader and uClinux
images to flash. uClinux kernel and fs images must be programmed to external flash.
The bootloader can be written either into internal or external flash.
There are three ways to program LPC22xx internal flash: ISP, IAP and parallel
programmer. For details, please refer the LPC22xx user manual.
To program external flash, we can adopt below methods:
-
By parallel flash programmer (hardware): for off-board programming
-
By Jtag interface and (Wringler or In-Circuit Emulator)
-
By Ethernet interface
-
By USB interface
For the latter 3 methods, there will have related software running on PC and connect PC
with board by corresponding interface. The software would be different according to your
flash vendor and part no.
5.4 Memory layout
The generated image files as well as bootloader will be programmed to board flash.
Bootloader will lead the system and start up from board flash. Then the uClnux kernel
can be started from flash directly or copied to RAM area for better speed performance.
Usually the memory size needed for uClinux system is as:
•
Minima
Flash: 2 MB; RAM: 2 MB
“Minima” means that only the uClinux kernel and necessary root file system can
run.
If the images are compressed to flash, the minimum flash size can be less to
512 kB.
•
Typical
Flash: 4 MB; RAM: 4 MB
A “Typical” system can include more than 1 file system, Ethernet driver, LCD
driver and some commonly used device drivers.
For video, audio or some complicated systems, they can take more memory
space.
6. Start up uClinux
6.1 Run uClinux on the board
If you have written the bootloader as well as uClinux kernel and file system images into
the flash, you are ready to run uClinux on your board.
•
Connect the board UART0 with PC COM port by serial cable
•
Open a serial terminal on the PC and set its parameters as "9600 8n1n"
•
Power on the board
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
17 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
Below is the example running process. It may be a little different according to your
system.
--------------------------------------------------------------------------------------------------------------------Linux version 2.6.11.8-ucLPC ([email protected]) (gcc version 2.95.3 2
0010315 (release)
Tue Nov 16 09:19:46 CST 2004
CPU: Philips-LPC22xx [22000000] revision 0 (ARMvundefined/unknown)
Machine: LPC2294, PHILIPS ELECTRONICS Co., Ltd.
On node 0 totalpages: 2048
DMA zone: 0 pages, LIFO batch:1
Normal zone: 2048 pages, LIFO batch:1
HighMem zone: 0 pages, LIFO batch:1
Built 1 zonelists
Kernel command line: root=/dev/ram0 initrd=0x81200000,1000K console=ttyS0
PID hash table entries: 64 (order 6: 512 bytes)
Memory: 8MB = 8MB total
Memory: 5896 KB available (994K code, 133K data, 48K init)
Calibrating delay loop... 3.57 BogoMIPS
Dentry cache hash table entries: 1024 (order: 0, 4096 bytes)
Inode-cache hash table entries: 1024 (order: 0, 4096 bytes)
Mount-cache hash table entries: 512 (order: 0, 4096 bytes)
checking if image is initramfs...it isn't (ungzip failed); looks like an ini
trd
Freeing initrd memory: 1000K
POSIX conformance testing by UNIFIX
Serial: 8250/16550 driver $Revision: 1.90 $ 2 ports, IRQ sharing disabled
ttyS0 at MMIO 0x0 (irq = 6) is a 16550A
ttyS1 at MMIO 0x0 (irq = 7) is a 16550A
RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize
loop: loaded (max 8 devices)
RAMDISK: romfs filesystem found at block 0
RAMDISK: Loading 948 blocks [1 disk] into ram disk... done.
VFS: Mounted root (romfs filesystem) readonly.
Freeing init memory: 48K
Shell invoked to run file: /etc/rc
Command: hostname Philips-LPC2294
Command: /bin/expand /etc/ramfs.img /dev/ram1
Command: mount -t proc proc /proc
Command: mount -t ext2 /dev/ram1 /var
Command: mkdir /var/tmp
Command: mkdir /var/log
Command: mkdir /var/run
Command: mkdir /var/lock
Command: mkdir /var/empty
Command: cat /etc/motd
Welcome to
____ _ _
/ __| ||_|
_
_| | | | _ ____ _
_ _ _
| | | | | | || | _ \| | | |\ \/ /
| |_| | |__| || | | | | |_| |/
\
| ___\____|_||_|_| |_|\____|\_/\_/
| |
|_|
For further information check:
http://www.nxp.com/external/uclinux
Command:
Command:
Command:
[13]
Command:
ifconfig lo 127.0.0.1
route add -net 127.0.0.0 netmask 255.255.255.0 lo
dhcpcd &
sh
Sash command shell (version 1.1.1)
/> Reading command line: Bad file descriptor
pid 14: failed 256
Execution Finished, Exiting
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
18 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
init: Booting to single user mode
Sash command shell (version 1.1.1)
/>ls -la
drwxr-xr-x 1 0
0
32 Jan
drwxr-xr-x 1 0
0
32 Jan
drwxr-xr-x 1 0
0
32 Jan
drwxr-xr-x 1 0
0
32 Jan
drwxr-xr-x 1 0
0
32 Jan
drwxr-xr-x 1 0
0
32 Jan
drwxr-xr-x 1 0
0
32 Jan
drwxr-xr-x 1 0
0
32 Jan
dr-xr-xr-x 18 0
0
0 Jan
lrwxrwxrwx 1 0
0
4 Jan
lrwxrwxrwx 1 0
0
8 Jan
drwxr-xr-x 1 0
0
32 Jan
drwxr-xr-x 7 0
0
1024 Jan
/> ps
PID PORT STAT SIZE SHARED %CPU COMMAND
1
S
163K
0K 7.3 /sbin/init
2
S
0K
0K 0.0 ksoftirqd/0
3
S
0K
0K 0.0 events/0
4
S
0K
0K 0.0 kblockd/0
5
S
0K
0K 0.0 pdflush
6
S
0K
0K 0.0 pdflush
8
S
0K
0K 0.0 aio/0
7
S
0K
0K 0.0 kswapd0
15
R
102K
0K 11.8 /bin/sh
/> cat /proc/meminfo
MemTotal:
6968 kB
MemFree:
4648 kB
Buffers:
1076 kB
Cached:
400 kB
SwapCached:
0 kB
Active:
1160 kB
Inactive:
300 kB
HighTotal:
0 kB
HighFree:
0 kB
LowTotal:
6968 kB
LowFree:
4648 kB
SwapTotal:
0 kB
SwapFree:
0 kB
Dirty:
0 kB
Writeback:
0 kB
Mapped:
0 kB
Slab:
700 kB
Committed_AS:
0 kB
PageTables:
0 kB
VmallocTotal: 4194303 kB
VmallocUsed:
0 kB
VmallocChunk: 4194303 kB
1
1
1
1
1
1
1
1
1
1
1
1
1
00:00
00:00
00:00
00:00
00:00
00:00
00:00
00:00
00:00
00:00
00:00
00:00
00:00
.
..
bin
dev
etc
home
lib
mnt
proc
sbin -> /bin
tmp -> /var/tmp
usr
var
/>cd var
/var>cd lucy
/var/lucy>hello
/******** Hello Philips! ********/
/******** Hello LPC22xx! ********/
/**** Welcome using uClinux for Philips LPC22xx! ****/
--------------------------------------------------------------------------------------------------------------------Under the uClinux shell, you can type some Linux command to check the effect.
E.g. “ls, ps, cat, cd, etc.”
And you can run your first “Hello, the World” program in the shell, too.
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
19 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
6.2 uClinux startup process
Fig 12 can give you a rough idea about uClinux internal startup process, for your
reference.
Check
processor id
Error
OK
Start
Dead loop
Jump to C code
start_kernel()
System initialization:
PLL,SP,MEMMAP,etc..
Print Linux version info
Decompress Image
Memory init
Interrupt init
Load Image
Timer init
Jump to uClinux kernel
and transfer parameters
Load device drivers
Mount file systems
Start init process
BootLoader
Kernel
Start Shell
Enter into Idle state, wait
for new command
Fig 12. uClinux start-up process
7. uClinux development
This section gives a brief introduction on how to develop device driver, how to develop
user applications and how to do debugging based on the established uClinux
development platform.
7.1 Develop device drivers
To develop user specific device drivers, here are some references:
•
Documents: uClinux-dist\linux-2.6.x\Documentation\driver-model\
•
Classical book: Linux Device Driver: the 2nd edition, by O’REILLY
Actually the more handy way is to find some similar or related device drivers under the
source code directory: uClinux-dist\linux-2.6.x\drivers. Especially when there exist
compatible device drivers, the development would become quite laborsaving. It becomes
porting instead of creating.
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
20 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
To develop the Ethernet driver of RTL8019AS, which is NE2000 compatible, we can find
the related source files here \uClinux-dist\linux-2.6.x\drivers\net: ne.c, 8390.c, 8390.h. By
providing some basic information ‘the SFR startup address, interrupt number, etc.’, we
can get the new RTL8019AS Ethernet driver for our own board.
7.2 Develop user applications
On how to develop user application program, there is a pretty good user guide under the
\Documentation directory of uClinux source code tree.
uClinux-dist\Documentation\Adding-User-Apps-HOWTO
By following the document step by step, we can create and run our first ‘Hello, the world!’
program in 1 hour.
7.3 Debugging
7.3.1 Debug OS kernel and device driver
There are several ways to debug uClinux kernel and device driver program. E.g.
1) AXD + MultiICE + MultiICE-Server
AXD: ADS Debugger by ARM company, running under Windows environment.
MultiICE: ARM Emulator by ARM company, parallel port interface to PC and JTAG
interface to the board.
MultiICE-Sever: driver program for MultiICE, running under Windows environment
2) arm-elf-gdb(insight) + MultiICE-gdb-server + MultiICE + MultiICE-Server
arm-elf-gdb(insight): GNU cross debugger for ARM architecture, running under Linux
environment. arm-elf-insight is the GUI version of arm-elf-gdb.
MultiICE-gdb-server: a server for ADS tools to debug GNU program, free provided by
ARM company and running under Windows environment.
MultiICE: same as above
MultiICE-Server: same as above
But until now, it seems there is no perfect method for source code awareness. Usually it
should be assisted by ‘printk’ – the original debugging method for Linux kernel
debugging. For using ‘printk’, the serial/UART interface should be initialized in the
bootloader previously.
7.3.2 Debug application program
Debugging uClinux application program is relatively easier than kernel debugging. By
using arm-elf-gdb and arm-elf-gdb server as a stuck on the user board, the user program
can be debugged under PC Linux environment.
Actually user can debug application program under PC Linux environment first and then
download to the board for further verification.
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
21 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
8. Legal information
8.1 Definitions
Draft — The document is a draft version only. The content is still under
internal review and subject to formal approval, which may result in
modifications or additions. NXP Semiconductors does not give any
representations or warranties as to the accuracy or completeness of
information included herein and shall have no liability for the consequences
of use of such information.
8.2 Disclaimers
General — Information in this document is believed to be accurate and
reliable. However, NXP Semiconductors does not give any representations
or warranties, expressed or implied, as to the accuracy or completeness of
such information and shall have no liability for the consequences of use of
such information.
Right to make changes — NXP Semiconductors reserves the right to make
changes to information published in this document, including without
limitation specifications and product descriptions, at any time and without
notice. This document supersedes and replaces all information supplied prior
to the publication hereof.
Suitability for use — NXP Semiconductors products are not designed,
authorized or warranted to be suitable for use in medical, military, aircraft,
space or life support equipment, nor in applications where failure or
malfunction of a NXP Semiconductors product can reasonably be expected
to result in personal injury, death or severe property or environmental
damage. NXP Semiconductors accepts no liability for inclusion and/or use of
NXP Semiconductors products in such equipment or applications and
therefore such inclusion and/or use is for the customer’s own risk.
Applications — Applications that are described herein for any of these
products are for illustrative purposes only. NXP Semiconductors makes no
representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
8.3 Trademarks
Notice: All referenced brands, product names, service names and
trademarks are property of their respective owners.
AN10389_1
Application note
© NXP B.V. 2007. All rights reserved.
Rev. 01 — 15 February 2007
22 of 23
AN10389
NXP Semiconductors
Getting started uClinux with LPC22xx
9. Contents
1.
1.1
1.2
1.3
2.
2.1
2.2
2.3
2.4
2.5
3.
3.1
3.2
3.3
4.
4.1
4.2
5.
5.1
5.1.1
5.1.2
5.2
5.3
5.4
6.
6.1
6.2
7.
7.1
7.2
7.3
7.3.1
7.3.2
8.
8.1
8.2
8.3
9.
Introduction .........................................................3
About uClinux ........................................................3
About LPC22xx .....................................................3
uClinux for LPC22xx..............................................3
Setup environment..............................................3
Install Linux on the PC ..........................................3
Grab source code packages..................................4
Make source code tree ..........................................4
Get and install cross toolchain...............................6
Hardware platform.................................................6
System configuration..........................................7
Distribution configuration .......................................7
Kernel configuration ............................................10
Application/library configuration...........................14
Build image ........................................................14
Make ...................................................................14
The results...........................................................14
Load image ........................................................15
Before loading .....................................................15
Interrupt vector table ...........................................15
Bootloader ...........................................................16
Load to RAM .......................................................16
Load to flash........................................................17
Memory layout.....................................................17
Start up uClinux.................................................17
Run uClinux on the board....................................17
uClinux startup process .......................................20
uClinux development ........................................20
Develop device drivers ........................................20
Develop user applications ...................................21
Debugging ...........................................................21
Debug OS kernel and device driver.....................21
Debug application program .................................21
Legal information ..............................................22
Definitions............................................................22
Disclaimers..........................................................22
Trademarks .........................................................22
Contents.............................................................23
Please be aware that important notices concerning this document and the product(s)
described herein, have been included in the section 'Legal information'.
© NXP B.V. 2007. All rights reserved.
For more information, please visit: http://www.nxp.com
For sales office addresses, email to: [email protected]
Date of release: 15 February 2007
Document identifier: AN10389_1